In the realm of installation engineering, for example, quick-action nuts consisting of several parts that are joined together and secured on the threaded rod are known as an alternative to standard nuts. Their advantage lies in the fact that they do not have to be twisted on from the end of the threaded rod, but rather, that they can be fastened directly to any desired place on the threaded rod. In particular, they can be employed in the production of multilayered suspended structures as well as for subsequently mounting an additional installation plane in an existing suspended structure.
European patent application EP 1 016 797 A2, for example, discloses a multi-part quick-action nut. This patent application teaches the approach of using an almost completely split standard nut as the quick-action nut, which can be opened by bending the web that remains after the nut is split, thus causing plastic deformation in the vicinity of the web. After the nut has been opened, it can be held over the threaded rod in any desired place, so that the nut parts can then be bent back plastically.
Another multi-part quick-action nut is known, for instance, from German patent DE 10 2006 035 404 B4. According to this patent, two completely separate nut parts are resiliently joined together by a spring.
In order to lock multi-part quick-action nuts, there is often a need for a locking element having a passage opening (e.g. a circular hole in the rail or in the joining part) which encircles the split nut, so that it is protected against accidental opening under load. Such a locking element is shown, for example, in U.S. Pat. No. 4,083,288 A. According to this patent, the locking element is configured in the form of a disk and it has a passage opening with a cylindrical centering surface through which the threaded rod can be inserted, as well as a conical locking surface that locks both nut parts.
Another nut that can be quickly fitted is disclosed in German patent DE 19904293 A. At http://www.tnb.com/shared/docs/kd—1_g_trapnut.pdf, a four-piece arrangement consisting of two split sheet metal plates having half-threads, a rivet and a locking pin is described. The arrangement is held in the open state at any desired place on the threaded rod and closed like a pair of scissors. Then, the locking pin is pressed with pliers, the arrangement is rotated into the desired position and firmly tightened with a wrench. http://www.cooperbline.com/pdf/Flyers/BA193S.pdf describes an approach involving a nut and a plate which are pressed into each other but which can nevertheless be rotated with respect to each other, and which each have a half-thread and an opening for the threaded rod. The arrangement is held in the open state—that is to say, when the openings on the nut and on the plate are oriented in the same direction—at any desired place on the threaded rod. Then the arrangement is closed and firmly tightened by turning the nut and the plate.